The present exemplary embodiment relates to extendable masts. It finds particular application in conjunction with portable masts that are intended to be rapidly deployed and or removed while in the field, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Various field mast designs are known in the art. Generally, a field mast is a transportable rapidly deployable support column having a height adjust system for raising or lowering an associated device. The associated device can include a communication, audio/video, and or lighting system or any other device whose function or performance is dependent on height or line of sight operation. Typical applications of such masts include both military and civilian settings where a mast must be erected quickly, quietly and or manually.
However, the prior art field mast assemblies are deficient in a number of ways. First, it is a typical and recurring problem that in the process of removing or collapsing the prior art field masts, the individual mast sections will bind and prevent the mast assembly from being placed into its fully collapsed state. The binding of the mast sections can occur from a variety of reasons, for example, debris trapped between the telescopic mast sections, high wind loads that create a bending moment in the mast sections, or simply lack of proper maintenance and or lubrication of the mast assembly.
In addition, the prior art masts include an open design winch assembly for raising or lowering the individual mast sections. Particularly in sandy or dry dusty regions, an open design winch assembly is prone to accelerated wear-out. This is due to debris or other aggregate materials accumulating on various internal operating components of the winch assembly, such as the bearings, drums, gears, ratchet assemblies, etc. Moreover, open winch designs create pinch hazards for the operators.
Furthermore, the prior art masts often include a winch assembly that is not easily detached from the mast assembly. In these cases, a fixed or permanent winch increases the transport weight and creates a bulky protrusion that inhibits the portability and efficient storage of the mast assembly.
Further still, the prior art mast assemblies include a fixed input-to-output reduction ratio for driving the winch. In these cases, either valuable time is lost in a system with excessive reduction or increased fatigue is experienced in a system with inadequate speed reduction.
Accordingly, it has been considered desirable to develop a new and improved field mast system which would overcome the foregoing difficulties and others while providing better and more advantageous overall results.